Drinking Montmorency tart cherry juice twice a day for two weeks helped increase sleep time among older adults suffering with insomnia. Study co-author Dr. Frank L. Greenway, director of the outpatient research clinic at the Pennington Biomedical Research Center at Louisiana State University, said an estimated one-quarter to one-third of U.S. adults age 65 and older have insomnia -- defined as trouble sleeping on average more than three nights per week. Insomnia is linked to a higher prevalence of chronic pain, high blood pressure, type 2 diabetes and a decline of cognitive function, or dementia. Many turn to sleeping pills; but this can increase the risk of falls in in seniors. "Sleeping pills may be an option for younger insomniacs, but for older people these medications quadruple the risk of falling, which can lead to broken hips and, often, earlier death," Greenway said in a statement. For the randomized crossover clinical trial, seven older adults with an average age 68 with insomnia drank 8 ounces of tart cherry juice twice daily for two weeks, followed by a two-week period during which they drank none of the juice. Afterward, the study subjects drank another beverage for a two-week period. The researchers studied the sleep of the study subjects controlled setting, using overnight polysomnography -- body functions monitored including brain, eye movements, skeletal muscle activation and heart rhythm -- during sleep to evaluate sleep efficiency, such as how long it takes someone to sleep and sleep duration. Greenway told the annual meeting of the American Society of Nutrition held in conjunction with the Experimental Biology meeting in San Diego that the study found those who drank the Montmorency tart cherry juice twice a day slept an average 84 minutes more compared to the placebo. Montmorency tart cherries are a natural source of melatonin, a hormone. Tart cherry juice helped increase tryptophan, an essential amino acid and a precursor to serotonin that helps with sleep. Tryptophan degradation is a known predictor of insomnia and is also related to inflammation, Greenway added. The findings were submitted for publication in a peer-reviewed journal. The Cherry Marketing Institute provided funding for the research, but had no role in the study design, data collection and analysis or preparation of the abstract or presentation.